ML20057C122
| ML20057C122 | |
| Person / Time | |
|---|---|
| Site: | 05200002 |
| Issue date: | 09/23/1993 |
| From: | Mike Franovich Office of Nuclear Reactor Regulation |
| To: | Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 9309270097 | |
| Download: ML20057C122 (48) | |
Text
/.hp-e$n 7~
e ncn
' D t
UNITED STATES jf f
- f ( i.i j NUCLEAR REGULATORY COMMISSION o
f WASHINGTON, D.C. 20555-0001
%..v...f September 23, 1993 Docket No.52-002 APPLICANT: ABB-Combustion Engineering, Inc. (ABB-CE)
PROJECT:
CE System 80+
i
SUBJECT:
PUBLIC MEETING 0F SEPTEMBER 16, 1993, TO DISCUSS CE SYSTEM 80+
PROTECTION AGAINST CONTAINMENT BYPASS DURING A STEAM GENERATOR TUBE RUPTURE (SGTR)
On September 16, 1993, a public meeting was held at the ABB-CE offices in Rockville, Maryland, between representatives of ABB-CE and the U.S. Nuclear Regulitory Commission (NRC). provides a list of attendees.
, is the material presented by ABB-CE. contains the ABB-CE preliminary SGTR evaluation.
The purpose of the meeting was to discuss potential design alternatives for the CE System 80+ design to prevent SGTR containment bypass (DSER Open Item 15.3.8-1).
The principle concern for this issue involves the potential for a main steam safety valve (MSSV) sticking open during an SGTR, resulting in an unisolable release path from the reactor coolant system to the environ-ment.
ABB-CE Conclusions Based on the recent SGTR analysis, ABB-CE committed to add two nitrogen-16 (N-16) monitors (one for each steam generator), with a latching mechanism, (indication / alarm lock) to assist operators in their diagnostic functions.
ABB-CE concluded in their preliminary evaluation that no automatic actuation system should be added to the present System 80+ design.
This conclusion was based on the evaluation of potential automatic SGTR features and that these design options present new uncertainties and potential challenges to overall plant safety.
i ABB-CE SGTR Evaluation ABB-CE presented a comprehensive study of design alternatives to automate the plant response during an SGTR event. System 80+ plant response for the present design (base case) versus plant response with the added design f
features were presented in terms of time-to-MSSV-lift. All analyses were performed assuming no operator action.
The potential design alternatives included:
i Automatic pressurizer auxiliary spray Automatic pressurizer gas venting
=
Automatic steam generator (SG) blowdown
=
Automatic bypass of the SG high level main steam isolation signal Automatic set point lowering on the turbine / steam bypass system 240032 g gt ggg ggy 9309270097 930923 m
PDR ADOCK 05200002 l'j A
. September 23, 1993 Best-estimate analyses were performed for the single tube SGTR case and the multiple tube (5) SGTR case. Assuming the steam bypass control system functions properly, the base-case evaluation demonstrated that operators would have more than 3 hours3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> to initiate mitigation actions after a single tube rupture before MSSVs are challenged.
For the base-case multiple tube rupture, MSSVs would be challenged after 30 minutes.
The results indicated that for the single tube case with automated features, only marginal improvement occurred until the MSSVs were challenged.
For the five-tube rupture case, the only design option that significantly increased the time-to-MSSV-lift involves the use of high capacity SG liquid blowdown.
Under this design option, the time-to-MSSV-lift was extended from 30 minutes to over 167 minutes.
Staff Comments /Aareements The staff stated that ABB-CE had performed a more rigorous evaluation than previous efforts on the SGTR issue.
In addition, ABB-CE presented design alternatives that were not identified in previous meetings (e.g., high-capacity SG blowdown). The staff also concurred that the addition of N-16 monitors and alarms should assist operators in the diagnosis of the event with prompt identification of the faulted SG.
Based on staff comments, the following commitments were made during the meeting:
(1) ABB-CE will qualify and quantify the improved ability of the System 80+
design to cope with an SGTR.
The scope of this response should capture inherent design characteristics that reduce the likelihood of core damage and plant risk from SGTR sequences. The quantification should demon-strate that the System 80+ design has substantive improvement (e.g., an order of magnitude) over the System 80 design for the SGTR containment bypass event. Design characteristics and features, such as improved event identification / diagnosis (with N-16), increased IRWST inventory and refill capability, potential use of the rapid depressurization system, and larger SGs, should be fully discussed.
(2) ABB-CE will investigate potential modification of the high-capacity SG liquid blowdown system. This modification entails the addition of a bleed line from the SG liquid blowdown line (from inside containment) to the in-containment refueling water storage tank. The bleed system would be regulated to maintain SG level, and ABB-CE should evaluate an auto-mated system versus a manually-actuated system.
m
._ September 23, 1993 i
(3) ABB-CE will submit computer plots of the plant response analyses for the base case and cases with the automatic design features.
ABB-CE also indicated that the commitments should' be fulfilled by October 4, 1993.
(Original signed by)
Michael X. Franovich, Project Manager Standardization Project Directorate Associate Directorate for Advanced Reactors and License Renewal j
Office of Nuclear Reactor Regulation
Enclosures:
As stated cc w/ent wures:
See next pa:.e DISTRIBUTION w/ enclosures:
Docket-File.
PDST R/F DCrutchfield TMurley/FMiraglia _
PDR MFranovich RPerch,-8H7 PShea DISTRIBUTION w/o enclosure _s:
e RBorchardt JMoore, 15G13 EJordan, MNBB3701 WRussell RJones, BE23 MRubin, 10E4 SSun, BE23 GGrant, 17G21 DDiec, 8E23 TKenyon JStrosnider,.7D4 NSaltos,10E4 AEl-Bassioni,10E4 JWiggins, 7026 AThadani, 8E2 RPalla,10E4 TCollins, 8E23 MMiller, 8E23 SMagruder ACRS (11)
WTravers Tenh(n 0FC:
LA:PDST:ADAR PM:PDST:
(
PDST:ADAR t
NAME:
PShea P
MXFrano/
tz o
RJ nes DATE:
09/g 3
09/p/93 09/,,i;/93 09//p /93 OFFICIAL RECORD COPY:
DOCUMENT NAME: MSUM0916.MXF l
l l
i
i l
l ABB-Combustion Engineering, Inc.
Docket No.52-002 cc: Mr. C. B. Brinkman, Acting Director l
Nuclear Systems Licensing ABB-Combustion Engineering, Inc.
)
1000 Prospect Hill Road Windsor, Connecticut 06095-0500 Mr. C. B. Brinkman, Manager Washington Nuclear Operations ABB-Combustion Engineering, Inc.
12300 Twinbrook Parkway, Suite 330 Rockville, Maryland 20852 Mr. Stan Ritterbusch Nuclear Systems ~ Licensing ABB-Combustion Engineering, Inc.
1000 Prospect Hill Road Post Office Box 500 Windsor, Connecticut 06095-0500 Mr. Sterling Franks U.S. Department of Energy NE-42 Washington, D.C.
20585 i
Mr. Steve Goldberg Budget Examiner 725 17th Street, N.W.
Washington, D.C.
20503 Mr. Raymond Ng 1776 Eye Street, N.W.
Suite 300 Washington, D.C.
20006 Joseph R. Egan, Esquire Shaw, Pittman, Potts & Trowbridge 2300 N Street, N.W.
Washington, D.C.
20037-1128 Mr. Regis A. Matzie, Vice President Nuclear Systems Development ABB-Combustion Engineering, Inc.
1000 Prospect Hill Road Post Office Box 500 Windsor, Connecticut 06095-0500
ABB-CE SYSTEM 80+
SGTR Containment Bypass Meeting September 16,1993 Rockville, Maryland NAME ORGANIZATION A. Thadani NRR/DSSA M. Franovich NRR/PDST M. Miller NRR/SRXB R. Borchardt NRR/PDST J. Wiggins NRR/DE N. Saltos NRR/SPSB M. Rubin NRR/SPSB R. Jones NRR/SRXB T. Wambach NRR/PDST S. Franks DOE P. Lang DOE F. Carpentino ABB-CE S. Ritterbusch ABB-CE J. Longo, Jr.
ABB-CE R. Harvey ABB-CE
Vats 4
A
+
a t
.I e
4
t SYSTEM 80 +... Containment Bypass i
ABB-CE /NRC Meeting... September 16,1993 6
Status of ABB-CE's evaluation of potential NSSS features to reduce demands on operators and delay MSSV opening.
6 9
k i
i
f AUGUST 16, 1993 NRC ABB-CE SENIOR MANAGEMENT MEETING COMMITMENTS AUGMENT TRANSIENT ANALYSIS BY ADDRESSING SINGLE TUBE RUPTURES PROVIDE AN ENGINEERED RESOLUTION TO MINIMIZE I
SGTR CONTAINMENT BYPASS BY 8/30/93 LEADING CANDIDATE BEING EVALUATED WAS N-16 SIGNAL ACTUATING AUTOMATIC ISOLATION OF FAULTED GENERATOR AND AUTOMATIC PRESSURIZER AUXILIARY SPRAYS p
k t
.u i
I 4
STATUS FOR THE SEPTEMBER 16, 1993 SGTR CONTAINMENT BYPASS MEETING SINGLE TUBE RUPTURE ANALYSIS COMPLETED AND SUBMITTED ENGINEERING SOLUTION TO MINIMIZE SGTR CONTAINMENT BYPASS RECOMMENDED BY ABB-CE.
FOR THE SYSTEM 80+ NSSS THE RECOMMENDED SOLUTION IS TO ADD TWO N-16 MONITORS (ONE PER STEAM GENERATOR) WITH LATCHING MECHANISM.
THIS GREATLY IMPROVES DIAGNOSTIC CAPABILITY FOR THE OPERATOR.
THE EARLIER CONCERN THAT OVERWHELMING THE SGTR CONTAINMENT BYPASS PROBLEM INTRODUCES OTHER PROBLEMS WAS I
CONFIRMED.
6 4
i
SYSTEM 80+ SGTR
- 1. ACCIDENT RECOVERY GOALS
- AVOID MSSV ACTUATION
- AVOID STEAM LINE FLOODING
- AVOID SG DRYOUT
- PRESERVE CORE SUBCOOLING
- MINIMlZE RCS-TO-SG LEAKAGE
- 2. RECOVERY ACTIONS REDUCE RUPTURED SG PRESSURE
f i
r i
i t
-i s
i SYSTEM 80+ SGTR RESULTS i
The present NSSS design delays MSSV opening for:
1 lube......... > 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> S tubes..........> 30 minutes l
The present NSSS design automatically protects the fuel
[
from damage. Hence, radiation releases are minimized.
Features which contribute to the delay include:
Auto SBCS to control SG pressure Auto FWCS to control SG level Enlarged SG to store leakage Early Rx Trip (low Press & DNBR) i 4
e w -
1
i I
Design Alternatives Considered i
- 1. N-16 Monitoring & Alarms I
- 2. N-16 Actuation Signal (in conjunction with another signa!)
l
- 3. Automatic PZR Blowdown
- a. Aux Spray
- b. RCGVS
- c. RDS
- 4. Automatic SG Blowdown
- a. Steam to condensor (i) ADV's (ii) Turbine bypass (w/ MSIS bypass)
(iii) Reduced turbine bypass pressure
- b. Liquid to condensor (or flash tank)
(i) High capacity (ii) Normal capacity i
5
?
i
OPERATING CONDITIONS & SETPOINTS 1.
OPERATING RCS PRESSURE, PSIA 2250 2.
OPERATING SG PRESSURE (100% POWER), PSIA 1000 3.
OPERATING PRESSURE (0% POWER), PSIA 1100 4.
SIAS SETPOINT PRESSURE, PSIA 1835 5.
CIIARGING PUMP SIIUTOFF PRESSURE, PSIA 3025 6.
SAFETY INJECTION PUMP SHUTOFF PRESSURE, PSIA 183S 7.
SBCS SETPOLNT PRESSURE, PSIA 1078 8.
MSIS SETPOINT - SG LOW PRESSURE, PSIA 870 9.
MSIS SETPOINT - SG HIGIl LEVEL, 7c WIDE RANGE 98 10.
MSSV SETPOINT PRESSURE FOR FIRST VALVE BANK, 1200 PSIA r
SYSTEM / COMPONENT CAPACITIES 1.
SGTR FLOW, LBM/SEC - 1 TUBE 44 @ 1800 PSIA
- 5 TUBES 173 @ 1600 PSIA 2.
SAFETY INJECTION FLOW PER PUMP, 25 @ 1800 PSIA LBM/SEC 168 @ 1600 PSIA 3.
CHARGING PUMP FLOW, LBM/SEC 17 @ 2250 PSIA 4.
AUX. SPRAY FLOW, LBM/SEC 17 @ 2250 PSIA 5.
RCGVS FLOW, LBM/SEC 14 @ 2500 PSIA 6.
RDS FLOW, LBM/SEC 238 @ 2500 PSIA i
7.
ADV FLOW PER VALVE, LBM/SEC (MIN) 264 @ 1000 PSIA
e TABLE 1
SUMMARY
OF THE DENEFITS & LIMITATIONS OF POTENTIAL DESIGN CHANGES l
1 DESIGN CHANGE BENEFIT (B)
LIMITATION (B) 1.
Automatically bypass Extends MSSV lift time from o Steam lines will flood MSIS on high SG level.
26 to 50 minutes for 5 tubes causing significant ruptured.
equipment damage.
o Conflicts with criterion 24 of Reg. Guide 1.153 which requires separation of Protection and Control Systems.
2.
Automatically initiate Very small extension of MSSV o Reduces RCS subcooling auxiliary pressurizer spray lift time.
o Increases pressurizer (APS).
level early complicating diagnosis.
o Some reverse leakage of unborated secondary water.
3.
Automatically open the Very small extension of MSSV o Reduces RCS subcooling Reactor Coolant Gas Vents lift time, o Increases pressurizer System (RCGVS).
level early complicating diagnosis.
o Some reverse leakage of unborated secondary water.
o Conflicts with criterion 24 of Reg. Guide 1.153 which requires separation of Protection and Control Systems.
m.-,.....-
..-m,--. -.. -..,
,.-,.m.__m,
..m-,_m--
.~.-,____.,,,%.r
.c
.,._w
.u,.,.
y y
.y,_g
TABLE 1
SUMMARY
OF THE BENEFITO & LIMITATIONS OF POTENTIAL DESIGN CRANGED DESIGN CHANGE BENEFIT (8)
LIMITATION (8) 4.
Automatically open the Small extension of MSSV lift o Reduces MSSV lift time SG liquid blowdown system.
time for 5 ruptured tubes.
for 1 tube ruptured.
o Violates containment isolation requirements.
o Conflicts with criterion 24 of Re-J. Guide 1.153 which requires separation of Protection and Control Systems.
5.
Automatically reduce Very small extension of MSSV o Pressure reduction post-trip SBCS pressure to lift time, limited to remain above 900 psia (vs. 1100 psia).
the low SG pressure MSIS setpoint (850 psia).
o Complicatec SBCS with potential impact on plant availability.
6.
Automatically bypass Allows secondary blowdown o Conflicts with required MSIS on low SG pressure.
through SBCS to the safety function for main condenser.
steam line breaks.
o-High steam generator level MSIS still occurs.
o Conflicts with criterion 24 of Reg. Guide 1.153 which requires separation of Protection and Control Systems.
m r
4
o' TABLE 1
SUMMARY
OF THE DENEFITS & LIMITATIOND OF POTENTIAL DESIGN CHANGES DESIGN CHANGE DENEFIT(B)
LIMITATION (B) 7.
Autematically open the-Delays or prevents SG o Core subcooling lost Rapid Depressurization overfilling and MSSV o Large reverse flow of System (RDS) on the lifting.
unborated water.
pressurizer.
o Conflicts with criterion 24 of Reg. Guide 1.153 which requires separation of Protection and Control Systems.
e s
a
,-n-s
-e-e,<
u w.,-
e
- + -
,c w-m-
r
-o
TABLE 3
SUMMARY
OF CASEB CTUDIED AUTO (2)
APPROXIMATE BYPASS MSSV LIFT MSIS AUTO AUTO AUTO SG*
TIME CASE #
- TUBES SBCS (HSGL)
APS RCGVS BLOWDOWN (MINUTES) 1 1
Auto @
No No No No 167+
1100 psia 2
5 Auto @
No No No No 30 1100 psia 3
1 Auto @
Yes No No No 167+
1100 psia 4
5 Auto @
Yes No No No 167+...
1100 psia SG over-fills at 50 minutes 5
1 Auto @
No Yes No No less than 1100 psia 167 6
5 Auto @
No Yes No No 29 1100 psia 7
1 Auto @
No No Yes No 167+
1100 psia 8
5 Auto @
No No Yes No 33 1100 psia 9
1 Auto @
No No No Yes, High 167+...
l 1100 psia Capacity SG empties l at 30 mins.
1 i
@ f'fR,1Q d 5
3o ~; Jo c -
m AUTO (2)
APPROXIMATE BYPASS MSSV LIFT MSIS AUTO
- AUTO AUTO SG TIME CASE #
- TUBES SBCS (HSGL)
APS RCGVS BLOWDOWN (MINUTES) 10 5
Auto @
No No No Yes, High 167+
1100 psia Capacity SG nearly empties at 10 mins.
11 1
Auto 0 No No No.
Yes, Normal 167+
1100 psia Capacity 12 5
Auto @
No No No Yes, Normal 30 1100 psia Capacity 13 1
Auto @
No No No No 167+
900 psia 14 5
Auto 0 No No No No 33 900 psia Notes:
(1)
SBCS Steam Bypass Control System (2)
Auto Bypass MSIS (HSGL)
Automatic bypass of the high SG level initiation of main steam line isolation.
(3)
Auto APS Automatic initiation of auxiliary pressurizer spray.
4..
(4)
Auto RCGVS
. Automatic initiation of RCS gas vent system.
(5)
Auto SG Blowdown... Automatic initiation of SG liquid blowdown system.
l l
i
~...,4 r
m..
.-4 m.
SEQUENCE OF EVENTS FOR CASE 1 STEAM GENERATOR TUBE RUPTURE (BASE CASE FOR 1 TUBE)
TDIE (Sec)
EVENT SETPOINT 0.0 Tube Rupture Occurs 1100 Pressurizer Backup Heaters Actuated on 2200 Low Pressurizer Pressure, psia 1289 Reactor Trips on Hot Leg Saturation Trip Signal i
1290 Turbine Trips 1291 Steam Bypass System Actuated on High Steam 1078 Generator Pressure, psia 1294 Pressurizer Pressure Reaches Safety Injection 1835 Actuation (SIAS) Setpoint, psia 1295 Main Feedwater Terminated on SIAS f
2370 Auxiliary Feedwater to Intact Steam Generator 20.09 Actuated on Low Level, ft above tube sheet 5680 Auxiliary Feedwater to Intact Steam Generator 40.46
-i Terminated on High Level, ft above tube sheet Main Steam Isolation Signal (MSIS) Generated 98 on High Level in the Damaged Steam Generator, % wide range level Main Steam Safety Valves (MSSVs) on Damaged 1200 Steam Generator Actuated on High Steam Generator Pressure, psia
- Event does not occur during the 10000 seconds of transient simulation.
3 l
SEQUENCE OF EVENTS FOR CASE 2 STEA51 GENERATOR TUBE RUPTURE (BASE CASE FOR 5 TUBES)
TI31E (Sec)
EVENT SETPOINT 0.0 Tube Rupture Occurs 130 Pressurizer Backup Heaters Actuated on 2200 Low Pressurizer Pressure, psia 149 Reactor Trips on Hot Leg Saturation Trip Signal 150 Turbine Trips 160 Steam Bypass System Actuated on High Steam 1078 Generator Pressure, psia 165 Pressurizer Pressure Reaches Safety Injection 1835 Actuation Signal (SIAS) Setpoint, psia 166 Main Feedwater Terminated on SIAS 1540 Main Steam Isolation Signal (MSIS) Generated 98 on High Level in the Damaged Steam Generator, % wide range level 1800 Main Steam Safety Valves (MSSVs) on Damaged 1200 Steam Generator Actuated on High Steam Generator Pressure, psia 6
^
SEQUENCE OF EVENTS FOR CASE 3 STEAM GENERATOR TUBE RUITUIE (1 TUBE)
WITH MSIS ON HIGH SG LEVEL BYPASSED TDIE (Sec)
EVENT SETPOINT 1
0.0 Tube Rupture Occurs 1100 Pressurizer Backup Ifeaters Actuated on 2200 Low Pressurizer Pressure, psia 1289 Reactor Trips on Hot Leg Saturation Trip Signal 1290 Turbine Trips 1291 Steam Bypass System Actuated on High Steam 1078 Generator Pressure, psia 1
1294 Pressurizer Pressure Reaches Safety Injection-1835 Actuation Signal (SIAS) Setpoint, psia 1295 Main Feedwater Terminated on SIAS 2370 Auxiliary Feedwater to Intact Steam Generator 20.09 Actuated on Low Level, ft above tube sheet 5680 Auxiliary Feedwater to Intact Steam Generator 40.46 terminated on High Level, ft above tube sheet l
Main Steam Isolation Signal (MSIS) Generated 98 on High Level in the Damaged Steam Generator, % wide range level Main Steam Safety Valves (MSSVs) on Damaged 1200 Steam Generator Actuated on High Steam Generator Pressure, psia
- Event does not occur during the 10600 seconds of transient simulation.
SEQUENCE OF EVENTS FOR CASE 4 STEAAf GENERATOR TUBE RUPTURE (5 TUBES)
WITH MSIS ON IIIGII SG LEVEL BYPASSED TLTIE (Sec)
EVENT SETPOINT 0.0 Tube Rupture Occurs 130 Pressurizer Backup Heaters Actuated on 2200 Low Pressurizer Pressure, psia 149 Reactor Trips on Hot Leg Saturation Trip Signal 150 Turbine Trips 160 Steam Bypass System Actuated on High Steam 1078 Generator Pressure, psia 165 Pressurizer Pressure Reaches Safety Icjection 1835 Actuation Signal (SIAS) Setpoint, psia 166 Main Feedwater Terminated on SIAS 1570 Main Steam Isolation Signal (MSIS) would have 98 been generated on High Level in the Damaged Steam Generator, % wide range level (signal bypassed for this case)
Main Steam Safety Valves (MSSVs) on Damaged 1200 Steam Generator Actuated on High Steam l
Generator Pressure, psia i
- Event does not occur during the first 10000 seconds of transient simulation.
)
1
SEQUENCE OF EVENTS FOR CASE S STEAM GENERATOR TUBE RUI'TURE (1 TUBE)
WITH AUXILIARY SPRAY ON N-16 INDICATION 9
TDIE (Sec)
EVENT SETPOINT 0.0 Tube Rupture Occurs 1100 Pressurizer Backup Heaters Actuated on 2200 Low Pressurizer Pressure, psia 1289 Reactor Trips on Hot Leg Saturation Trip Signal 1290 Turbine Trips 1291 Steam Bypass System Actuated on High Steam 1078 Generator Pressure, psia 1294 Pressurizer Pressure Reaches Safety Injection 183S Actuation Signal (SIAS) Setpoint, psia 1810 Pressurizer Fills, Level (%)
100 2000 Pressurizer Saftey Valves Open on High 2500 Pressurizer Pressure, psia s
Main Steam Isolation Signal (MSIS) Generated 98 on High Level in the Damaged Steam Generator, % wide range level Main Steam Safety Valves (MSSVs) on Damaged Steam Generator Actuated on High Steam Generator Pressure, psia
- Event is expected to occur in less than 10000 seconds.
t P
h
s SEQUENCE OF EVENTS FOR CASE 6 STEAM GENERATOR TUBE RUITURE (5 TUBES)
WITH AUXILIARY SPRAY ON N-16 INDICATION TIME (Sec)
EVENT SETPOIhT 0.0 Tube Rupture Occurs 130 Pressurizer Backup Heaters Actuated on 2200 Low Pressurizer Pressure, psia 149 Reactor Trips on Hot Leg Saturation Trip Signal 150 Turbine Trips 160 Steam Bypass System Actuated on High Steam 1078 Generator Pressure, psia 165 Pressurizer Pressure Peaches Safety Injection 1835 Actuation Signal (SIAS) Setpoint, psia 166 Main Feedwater Terminated en SIAS 1600 Main Steam Isolation Signal (MSIS) Generated 98 on High Level in the Damaged Steam Generator, % wide range level 1750 Main Steam Safety Valves (MSSVs) on Damaged 1200 Steam Generator Actuated on High Steam Generator Pressure, psia I
4 SEQUENCE OF EVENTS FOR CASE 7 STEAM GENERATOR TUBE RUPTURE (1 TUBE)
WITH RCGV ACTUATED ON N-16 INDICATION I
i TI3IE (Sec)
EVENT SETPOINT 0.0 Tube Rupture Occurs 1100 Pressurizer Backup Heaters Actuated on 2200 Low Pressurizer Pressure, psia 1289 Reactor Trips on Hot Leg Saturation Trip Signal l
1290 Turbine Trips 1291 Steam Bypass System Attuated on High Steam 1078 Generator Pressure, psia 1294 Pressurizer Pressure Reaches Safety Injection 1835 Actuation Signal (SIAS) Setpoint, psia 1295 Afain Feedwater Terminated on SLE F
3250 Auxiliary Feedwater to Intact Steam Generator 20.09 Actuated on Low level, ft above tube sheet 6570 Auxiliary Feedwater to Intact Steam Generator 40.46 Terminated on High Level, ft above tube sheet hiain Steam Isolation Signal (htSIS) Generated 98 on High Lesel in the Damaged Steam Generator, % wde range level hiain Steam Safety Valves (A1SSVs) on Damaged 1200 Steam Generator Actuated on High Steam Generator Pressure, psia
- Event does not occur during the 10000 seconds of trasient simulation.
SEQUENCE OF EVENTS FOR CASE 8 STEAAf GENERATOR 'll'3E RUPTURE (5 TUBES)
WITH RCGV ACUTUATED ON N-16 INDICATION TIAIE (Sec)
EVENT SETPOINT 0.0 Tube Rupture Occurs 130 Pressurizer Backup Heaters Actuated on 2200 Low Pressurizer Pressure, psia 149 Reactor Trips on Hot Leg Saturation Trip Signal 1
l 150 Turbine Trips 160 Steam Bypass System Actuated on High Steam 1078 Generator Pressure, psia 165 Pressurizer Pressure Reaches Safety Injection 1835 Actuation Signal (SIAS) Setpoint, psia 166 Main Feedwater Terminated on SIAS 1800 Alain Steam Isolation Signal (MSIS) Generated 98 on High Level in the Damaged Steam i
Generator, % wide range level l
l l
2000 Main Steam Safety Valves (MSSVs) on Damaged 1200 Steam Generator Actuated on High Steam Generator Pressure, psia
SEQUENCE OF EVENTS FOR CASE 9 STEAM GENERATOR TUBE RUPTURE (1 TUBE)
WITH SG BLOWDOWN (HIGH) ON N-16 INDICATION TIME (Sec)
EVENT SETPOINT 0.0 Tube Rupture Occurs 1100 Pressurizer Backup Heaters Actuated on 2200 Low Pressurizer Pressure, psia 1289 Reactor Trips on Hot Leg Saturation Trip Signal 1290 Turbine Trips 1291 Steam Bypass System Actuated on High Steam 1078 Generator Pressure, psia 1294 Pressurizer Pressure Reaches Safety Injection 1835 l
Actuation Signal (SIAS) Setpoint, psia l
1295 Main Feedwater Terminated on SIAS l
1295 Steam Generator Blowdown (High) Actuated on Damaged Steam Generator on N-16 Indication
& SIAS 1850 Damaged Steam Generator Dries Out 2210 Auxiliary Feedwater Actuated to Intact Steam 20.09 Generator on Low Level, ft above tube sheet 2868 Main Steam Isolation Signal (MSIS) Generated 870 on Low Pressure in the Damaged Steam Generator, psia 5843 Auxiliary Feedwater to Intact Steam Generator 40.46 Terminated on High Level, ft above tube sheet Main Steam Safety Valves (MSSVs) on Damaged 1200 Steam Generator Actuated on High Steam Generator Pressure, psia
- Event does not occur during the 10000 seconds of transient sidiuTation.
SEQUENCE OF EVENTS FOR CASE 10 STEAM GENERATOR TUBE RUPTURE (5 TUBES)
WITH SG BLOWDOWN (HIGH) ON N-16 INDICATION TIME (Sec)
EVENT SETPOLNT 0.0 Tube Rupture Occurs 130 Pressurizer Backup Heaters Actuated on 2200 Low Pressurizer Pressure, psia 149 Reactor Trips on Hot Leg Saturation Trip Signal 150 Turbine Trips 160 Steam Bypass System Actuated on High Steam 1078 Generator Pressure, psia 165 Pressurizer Pressure Reaches Safety Injection 1835 Actuation Signal (SIAS) Setpoint, psia 550 Auxiliary Feedwater to Intact Steam Generator 20.09 Actuated on Low Level, ft above tube sheet 1380 Main Steam Isolation Signal (MSIS) Generated 870 on Low Steam Generator Pressure, psia Main Steam Isolation Signal (MSIS) Generated 98 on High Level in the Damaged Steam Generator, % wide range level Main Steam Safety Valves (MSSVs) on Damaged 1200 Steam Generator Actuated on High Steam Generator Pressure, psia
- Event does not occur during the 10000 seconds of transient simulation time.
SEQUENCE OF EVENTS FOR CASE 11 STEAM GENERATOR TUBE RUPTURE (1 TUBE)
WITH SG BLOWDOWN (NOM.) ON N-16 INDICATION TI',IE (Sec)
EVENT SETPOINT 0.0 Tube Rupture Occurs 1100 Pressurizer Backup Heaters Actuated on 2200 Low Pressurizer Pressure, psia 1289 Reactor Trips on Hot Leg Saturation Trip Signal 1290 Turbine Trips 1291 Stenra Bypass System Actuated on High Steam 1078 Generator Pressure, psia 1294 Pressurizer Pressure Reaches Safety Injection 183S Actuation Signal (SIAS) Setpoint, psia 1295 Main Feedwater Terminated on SIAS 2370 Auxiliary Feedwater Actuated to Intact Steam 20.09 Generator on Low Level, ft above tube sheet 5680 Auxiliary Feedwater to Intact Steam Generator 40.46 terminated on High Level, ft above tube sheet Main Steam Isolation Signal (MSIS) Generated 98 on High Level in the Damaged Steam Generator, % wide range level Main Steam Safety Valves (MSSVs) on Damaged 1200 Steam Generator Actuated on High Steam Generator Pressure, psia
- Event does not occur during the 10000 seconds of transient simulation.
w m
SEQUENCE OF EVENTS FOR CASE 12 STEAM GENERATOR TUBE RUPTURE (5 TUBES)
)
WITII SG BLOWDOWN (NOM.) AT N-16 INDICATION TIME (Sec)
EVENT SETPOINT
\\
0.0 Tube Rupture Occurs 130 Pressurizer Backup Heaters Actuated on 2200 Low Pressurizer Pressure, psia
~
149 Reactor Trips on Hot Leg Saturation Trip Signal J
150 Turbine Trips 160 Steam Bypass System Actuated on High Steam 1078 Generator Pressure, psia 165 Pressurizer Pressure Reaches Safety Injection 1835 Actuation Signal (SIAS) Setpoint, psia n
166 Main Feedwater Terminated on SIAS 1640 Main Steam Isolation Signal (MSIS) Generated 98 on High Level in the Damaged Steam Generator, % wide range level 1830 Main Steam Safety Valves (MSSVs) on Damaged 1200 Steam Generator Actuated on High Steam Generator Pressure, psia
a I
SEQUENCE OF EVENTS FOR CASE 13 STEAM GENERATOR TUBE RUPTURE (1 TUBE)
WITH STEAM BYPASS SYSTEM SETPOINT RESET TO 900 PSIA
~
TIME (Sec)
EVENT SETPOLNT 0.0 Tube Rupture Occurs 1100 Pressurizer Backup Heaters Actuated on 2200 Low Pressurizer Pressure, psia j
1289 Reactor Trips on Hot Leg Saturation Trip Signal i
i 1290 Turbine Trips 1291 Ste;un Bypass System Actuated on High Steam 1078 Generator Pressure, psia 1294 Pressurizer Pressure Reaches Safety Injection 1835 Actuation Signal (SIAS) Setpoint, psia 1295 Main Feedwater Terminated on SIAS 2185 Auxiliary Feedwater to Intact Steam Generator 20.09 Actuated on Low Level, ft above tube sheet 2390 Steam Bypass closes on Low Steam Generator Pressure 2720 Steam Bypass reopens on High Steam Generator 900 4
pressure, psia 5740 Auxiliary Feedwater to Intact Steam Generator 40.46 Terminated on High Level, ft above tube sheet Main Steam Isolation Signal (MSIS) Generated 98 on High Levelin the Damaged Steam Generator, % wide range level Main Steam Safety Valves (MSSVs) on Damaged 1200 Steam Generator Actuated on High Steam Generator Pressure, psia
- Event does not occur within the 10000 seconds of transient simulation time.
SEQUENCE OF EVENTS FOR CASE 14 STEA31 GENERATOR TUBE RUPTURE (5 TUBES)
WITH STEA31 BYPASS SYSTEM SETPOINT RESET TO 900 PSIA TIAIE (Sec)
EVENT SETPOINT 0.0 Tube Rupture Occurs 130 Pressurizer Backup Heaters Actuated on 2200 Low Pressurizer Pressure, psia 149 Reactor Trips on Hot Leg Saturation Trip Signal 150 Turbine Trips 160 Steam Bypass System Actuated on High Steam 1078 Generator Pressure, psia 165 Pressurizer Pressure Reaches Safety Injection 1835 Actuation Signal (SIAS) Setpoint, psia 166 Main Feedwater Terminated on SIAS 1700 Main Steam Isolation Signal (MSIS) Generated 98 on IIigh Level in the Damaged Steam Generator, % wide range level 2000 Main Steam Safety Valves (MSSVs) on Damaged 1200 Steam Generator Actuated on High Steam Generator Pressure, psia
e p
I O
P l
sYsTIM 30+
CONTAINXINT BYPAES EUXMARYt A comprehensive study was conducted of alternative ways to automate the behavior of the System 80+ NSSS during a SGTR event.
The objective was to maximize the time available for operator diagnosis of the event and for required manual recovery actions.
A specific
~
ebjective of this study was to maximize the time prior to the Main Steam Safety Valves (MSSVs) lifting.
If lifting is delayed for a significant time, concerns over the containment bypass represented j
by assumed MSSV malfunctions are alleviated.
The present System 80+ design was analyzed to define the time to MSSV lif ting for the ruptures of one to five tubes.
Figure 1 shows the time varies f rom greater than 3 hours3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> for one tube to about one half hour for five tubes.
These results are based on a best-estimate analysis which credits the availability of normal electrical power sources and normal NSSS control systems, i
Under these best-estimate conditions, it is shown that System 80+
allows a fairly significant time for diagnosis and subsequent-1 operator actions.
It was the purpose of this study to identify practical design options which could further improve the operator's diagnentic capability and extend the time period prior to MSSV lifting without introducing other safety concerns.
Table 1 sur.marizes the benefits and limitations for the various design options reviewed.
The present System 80+ Steam Bypass Control System allows the j
operator more than 3 hours3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> to take mitigating action after one tube rupture before the M9SVs are challenged.
Thus for this scenario, l
no additional design options are required.
1
/
1
nA-L M
_m a
A 1.
5L m--
6-4 If a five tube rupture scenario is considered, the various design options studied offer only small increases in operator time while causing significant damage, reduction of safety margins and/or special interfacing of non-safety and safety grade equipment to comply with regulatory guidance for maintaining separation of protection and control systems.
Thus, it is recommended that o
No Automatic Actuation Systems be added to the present System 80+ design.
o Pending additional design implementation, two N-16 monitors (one for each steam generator) be installed to assist the operator in his diagnostic functions.
1 I
1 l
5
-e-
- - - ~
a
,,w--
r-v-
e
=
4 Discussion of Desien Ontions Ivaluatedt-The Steam Generator Tube Rupture (SGTR) event challenges several safety systems and requires eventual diagnosis and manual recovery actions by the operator.
The safety systems involved are (1)
Reactor Trip (2)
Safety Injection Actuation Signal (SIAS)
(3)
Containment Isolation Actuation Signal (SIAS)
(4)
Main. Steam Isolation Signal (MSIS)
(5)
Emergency Feedwater Actuation Signal (EFAS)
(6)
Main Steam Safety Valva (MSSV) Lifting The SGTR event also activates the normal NSSS control systems which can act to benefit the automated behavior of the plant.
The following automatic control actions occurt j
(1)
Steam Bypass Control System (SBCS) opens the turbine bypass to the condenser lowering steam pressure.
(2)
Main Feedwater Control System (FWCS) initiates f
post-trip runback followed by feedwater isolation.
(3)
Pressurizer Pressure and Level Control System actuates heaters and charging flow.
1 The present study considered the effects of these safety and control actions along with potential design changes which could significantly extend the time available prior to Main Steam Safety l
Valve (MSSV) lifting.
Ruptures of one to five SG tubes were evaluated.
The potential design changes evaluated included:
(1)
Automated Auxiliary Pressurizar Spray (APS) to lower pressure and leak flowrate.
(2)
Automated Pressurizer Gas Vent opening to lover.
.[
pressure and leak flowrate.
(3)
Automated SG steam blowdown to a lowered pressure using t
the BBCS.
3 i
)
A k
(4)
Automated SG liquid blowdown to offset the high level caused by the leak.
(5)
Automatic bypass of the SG high level MSIS.
Figure 2 provides a simplifie-chematic of the secondary system and Table 2 provides an inventory of the valves in the secondary system.
A thorough review was conducted to identify all possible paths to reduce steam pressure and delay MSSV actuation. The final choices were selected for analysis.
Table 3 summarizes fourteen best-estimate cases run to assess the The best-perfor=ance of the System 80+ NSSS during SGTR events.
estimate analyses utilized the CEPAC transient simulation code.
I Normal onsite and of fsite electrical power sources were assumed as well as normal NSSS control system actions.
2 CA133__ _1__ and 1 (one & five tubes, respectively) are reference cases t
which depict the results for the present System 80+ design without i
adding any new features.
The time available prior to actuating the MSSVs is greatrr than 167 minutes for one tube ruptured and 30 minutes for five tubes ruptured.
These cases result in a high steam generator level which causes an automatic main steam l
l isolation for equipment / investment protection purposes.
The high level setpoint which causes this main steam isolation represents a 3
remaining unfilled volume inside the SG shall of about 2,000 ft.
Nonetheless, the steam line isolation renders the turbine / steam bypass system ineffective and the SG pressure rises to the MSSV lift pressure in several minutes.
CAtss_J_and 4 consider a potential change to the MSIS such that a coincident 2 of 4 channel reactor trip signal and a 2 of 2 channel N-16 steam line detector signals causes a bypass of the nornal MSIV closure signal.
This allows the turbine / steam bypass system to continue to function.
The time of MSSV lift for one tube is j
greater than 167 minutes (and of case, not actual lift time) and for five tubes the MSSV lift time was extended from 30 minutes for
+
.1 Case 2 to over 167 minutes (Case 4).
For this case, however, water is expected to enter the steam lines after 30 minutes and the lines would be solid after 50 minutes.
The steam lines upstream of the MSIVs are designed for this but not the downstream piping and equipment.
Thus, this approach risks significant damage to the plant.
Cases 5 and a consider a potential change to automatically initiate auxiliary pressurizar spray ( APS). The ef fectiveness of the APS is limited as the pressurizer steam space is eliminated by condensation and the spray water plus the High Pressure Safety Injection (HPSI) water cause RCS repressurization.
The repressurization increases the leak flow which accelerates SG l
filling, MBIS, and MSSV lifting.
The action of the spray also leads to an early pressurizer level increase which could complicate the operator's diagnosis of the SGTR event since a reduced level would be expected.
In addition, some reverse leakage of unborated SG water to the RCS will occur.
Cases 7 and a consider a potential charge to automatically open the Reactor Coolant Gas Vent System (RCGVS) valves on the pressurizar.
This depressurizes the primary side by blowing steam into the In-Containment Refueling Water Storage Tank (IRWST).
The effects on pressurizer pressure and level and MSSV lift time are similar to the auxiliary pressurizer spray option.
The pressurizer fills early, complicating diagnosis and little is gained in MSSV lift leakage of unborated water into the primary time.
Some reverso system is possible.
Case 5 through 12 consider a potential change to auto =atically initiate SG liquid blowdown to the condenser or blowdown flash tenh.
The initiation logic would use a coincident 2 of 2 channels high SG 1evel signals and 2 of 2 N-16 steam line detector signals to open.
Cases 9 and 10 consider opening the high capacity system (10% of full power feedvater flow) for one and five ruptured tubes, respectively.
Cases 11 and 12 consider the normal capacity system
)
y (0.2 to 1% of full power.feedwater flow) for one and five ruptured Y
tubes, respectively.
The high capacity liquid blowdown significantly extends the time for MSSV lifting.
However, the ruptured SG either empties or nearly empties reducing the benefit of decontamination (scrubbing) of the radiation source in the break flow.
The normal capacity liquid blowdown, on the other hand, was shown to have an insignificant effect on extending the MSSV lift time for both one tube ruptured (Case 11 versus Case 1) and five ruptured tubes (Case 12 versus Case 2).
The SG liquid blowdown system is currently required to be isolated automatically as part of the System 80+ containment isolation function.
Special consideration and interpretation of NRC's regulatory guidelines for designing plant protection systems (e.g.,
criterion 24 of Reg. Guide 1.153 which also references IEEE 603 and IEEE 279) and maintaining separation between the safety snd non-l safety electrical systems (e.g., Reg. Guide 1.75 which references The IEEE 384) may be necessary to bypass this isolation signal.
interf acing of the control grade blowdown actuation with the safety grade isolation system valves will entail significant complexities including a new containment piping penetration and valves dedicated to this SGTR function.
Furthermore, the high capacity portion of the present blowdown system is not designed for continuous operation.
i Cny 13 and 14 consider a potential change to the-turbine / steam bypass control system to regulate the steam pressure to a lower post-trip value upon an N-16 signal.
The present SBCS opens l
following a reactor / turbine trip and regulates pressure to about l
1100 paia.
If a coincident N-16 signal occurs, then the pre,ssure would be reduced to about 90D psia.
This increases the margin to the MSSV lift pressure (1200 pala) yet remains above the low pressure MSIS setpoints (850 psia). This potential change tends to
I-l t
increase leak flowrate but also in,
.ses ths turbine / steam bypass e
flowrate such that the MSSV lift tima.following five ruptured tubes f
is extended from 30 minutes (Case 2) to 33 minutes (Case 14).
This I
small benefit is insuf ficient to warrant the complexity introduced l
into the SBCS.
t t
[
?
a
?
i 9
I i
e
?
't
TABLE 1 DUMMARI OF THE BENETITS & LIMITATIONS OF POTENTIAL DESIGN CHANGES DERIGN CHANGE BENEFIT (0)
LIMITATIOM (8) 1.
Automatically bypass Extends MSSV lift time fros o Steam lines will flood MSIS on.high SG 1evel.
26 to 50 minutes for 5 tubes causing significant equipment damage.
ruptured.
o Conflicts with criterion 24 of Reg. Guide 1.153 which requires separation of Protection and Control Systems.
2.
Automatically initiate Very small extension of MSSV o Reduces RCS subcooling auxiliary pressurizer spray lift time, o Increases pressurizer level early complicating C>O (APS).
diagnosis.
o Some reverse leakage of unborated secondary water.
3.
Automatically open the Very small extension of MSSV o Reduces RCS subcooling Reactor Coolant Gas Vents lift time, o Increases pressurizer level early cosplicating System (RCGVS).
diagnosis.
o Some reverse leakage of unborated secondary water.
o Conflicts with criterion 24 of Reg. Guide 1.153 which requires separation of Protection and Control Systems.
e
TABLE 1 DUMMARY OF THE DENEFITS & LIMITATIONr,OF POTENTIAL DESIGN CHANGES
.e.e BENEFIT (8)
LIMITATION (B)
DESIGN CfrANGE 4.
Automatically open the Small extension of MSSV lift o Reduces MSSV lift time SG liquid blowdown system.
time for 5 ruptured tubes.
for 1 tube ruptured.
o Violates containment isolation requirements.
o Conflicts with criterion 24 of Reg. Guide 1.153 which requires 89paration of Protection arvi Control Systems.
5.
Automatically reduce Very small extension of MSSV o Pressure reduct'2' limited to remain above post-trip SBCS pressure to lift time.
900 psia (vs. 1100 psia).
setpoint (850 pain).
o complicates SBCS with potential impact on plant availability.
6.
Automatically bypass Allows secondary blowdown o conflicts with required MSIS on low SG pressure, through SBCS to the safety function for main steam line breaks.
condenser.
o High steam generator level MSIS still occurs.
o Conflicts with criterion 24 of Reg. Guide 1.153 which requires separation of Protection and Control Systems.
TABLE 1 SU)OOLRY OF THE BENEFITS & LIMITATIONS OF R aWTIAL DESIGN CHANGES DESIGN CHANGE B
IT (B)
LIMITATION (5) 7.
Automatically open the Delays or prevents SG o Core subcooling lost Rapid Depressurization overfilling and M55V o Large reverse flow of System (RDS) on the
- lifting, unborated water.
o conflicts with criterion pressurizer.
24 of Reg. Guide 1.153 which requires separation of Protection and Control Systems.
~
O I'
i e
l
. _. _.... ~...,.,.... -, _.
taux a SYSTEM 80+ SECONDARY SYSTEM VAI.VES VALVE AITTOMATIC NO VAINES VALVE OPERATOR SAFETY SAFETY ACTUATION MANUAL TITLE PER SG TYPE TYPE CLASS FUNCTION ON CONTROL Main Stean '
2 Clobe Pneumatic 2
To close MSIS Open/
Close Inolation Valves Main Steam Isol.'
2 Gate Pneumatic 2
To close MSIS Open/
Close Hypane Valven Hain Stean Safety 10 Safety Self 2
To open High SG None Valves Actuated Preneure Atmospheric Dump 2
Globe Solenoid 2
To open None Throttle Valven Steam Bypass 8
Globe Pne7matic 4
None Hlgh SC Throttle 2
Preneure Control Valven Blowdown t.
2 Gate Motor 2
To close EPAS, CIAS Open/
MSIS, AFAS Close Recirc. Valves Main Feedwater '
4 Cate Pneematic 2
To close MSIS Open/
Clone Isolation valven Emergency Feed.
4 Gate Motor 2
To open on E7AS, AFAS Open/
Isolation Valves AFAS, ETAS MSIS Close
~
To close on l
MSIS Emergency Feed.
1 Gate Pneumatit 2
Steam Supply To open Close Sampling Sys.'
4 Globe Solenoid 2
ETAS, CIAS Open/
To Clone MSIS, AFAS Clone Valves Recirculation '
1 Cate Solenoid 2
Remain None Ogw=n/
closed Close Wet Layup Valves Nitrogen Sys.
2 Globe Manual 2
Remain None Open/
closed Close Valves 1 designates containment isolation valves 2 8 valves total located on Main Steam Header CIAS 'contalment Isolation Actuation Signal AFAS - Alternate Emergencf FeMwater Actuation Signal (high containroent pressure or icw (Iow steam generator le-il) pressuritnr preneure)
EFAS - Energency Peedwater Actuation Signal MSIS - Main Steam Inolation Signal (1pw steam generator level)
(low nteam generator pressure, or Instrument Root Valves are not included high steam generator level or high containment presourn)
.=
i l
TABLE 3 BUMMARY OF CASES STUDIED i
l l
AUTO (2)
APPROXIMATE MSSV LIFT i
BYPASS MSIS AUTO AUTO"#
AUTO SG'"
TIME UI CASE I f TUDES SBCS "
(IISGL)
APS RCGVS BLOWDOWN (MINUTES)
I 1
1 Auto @
No No No No 167+
i 1100 psia 2
5 Auto 0 No No No No 30 t
1100 psia j
3 1
Auto 9 Yes No No No 167+
1100 psia 1
4 5
Auto G Yes No No No 167+...
SG over-1100 psia fills at 50 i
minutes S
1 Auto 9 No Yes No No less than t
167 1100 psia 6
5 Auto e No Yes No No 29 1100 psia 7
1 Auto @
No No Yes No 167+
f l
1100 psia 8
5 Auto e No No Yes No 33 1100 psia 9
1 Auto @
No No No Yes, High 167+...
1100 pela Capacity SG empties at 30 mins.
, _. _. _. _.. _. _. ~., _ -, _ _
- ~.. - - _,. _... _. _.. - - -., _ _ _.. _
a::-
APPROXIMATE AUTO MSSV LIPP BYPASS N
MSIS AUTO
APS RCGVS BLOWDOWN (MINUTES) 10 5
Auto 6 No No No Yes, High 167+
1100 psia Capacity SG nearly enpties at 10 mins.
11 1
Auto e No No No Yes, Normal 167+
1100 psia Capacity 12 5
Auto 9 No No No Yes, Normal 30 1100 psia Capacity 13 1
Auto e No No No No 167+
900 paia G
14 5
Auto e M-1 No No No 33 900 psia notes (1)
SBCS Steam Bypass Control System (2)
Auto Bypass MSIS (HSGL)
Automatic bypass of the high SG 1evel initiation of main steam line isolation.
(3)
Auto APS... Automatic initiation of auxiliary pressurizer spray.
(4)
Auto RCGVS... Automatic initiation of RCS gas vent system.
(5)
Auto SG Blowdown... Automatic initiation of SG liquid blowdown system.
l I
l L -....
.-.. ~
~
c.
(
FIGURE 1 SYSTEM'80+ MULTIPLE SGTR MSSV Lil-T TIME % NO. OF TUBES RUPTURED II 10 Best Estimate Analysis:
9 AC power available Normal NSSS Control Systen Actions eno 8
Z O-7 ea C-d!
6 s a E.8 5
5 3
4 2
3
- 2 i
3 O
1 2
3 4
5 6
NUMBER OFTUBES RUI'TURED
,w-
=
wr
.,*,.*e--w,.w
,<ev.m u-
.-,a__
u, e me
--ir,.
w
, re -*
-r
--,irv e v v u-e
--1,,-
.-w
-w
-,y a
n-.
.-,-wy.ug--a.-,-w,,w wv,,-,-e..reww.,--e~ww.se,+e-,,ws._vwvw-
- a
- --+
.--m--ew-w
4 d 0a 7Te
}
c As 3
- o. A t
e r.
SscI o'
C, Er o SWsS O
lA L
At 1
Co 5
c Os SdES r
SaVA I
LAT L
0 MO VE Eg H
y :Ms N
0 1
I TR D
gL uAE RW WAZD A
U V
TD AEUA uT A E S UH Q
E m
f CN YU s O4 d
sv' s
S Q%
v,OI G
P is M
u u
S
+
S O
O S
S G
M O
O u
T H
M T
A T
T A
A A
K V
R D
V-V S
N E
A D
C A
S 2
D A
WJ T
E A
F-N R
~
E U
H S
G S
I N
F A
O G
o F
C s
s S
S s
L o
0 A
u u
u u
E T
T T
i E
V A
A
)
A A
)
E
)
5 5
M2O D
)
5
(
(
AGB 5
v v
(
s s
SSA v
s s
s u
s u
~
s u
S jj;lll!
l l
jjljlI K.
!,l F
E j
F
.s W
iw c
F 9
S Eh l
I C
F a
I
(
N
_2 r
s
]
e 4
u1 nE W
Ig-]u4 2
N r
D sG Id
\\
sC I
L
[1
/.
b @
OLO V
g h. @W-I O
L L
~
- W
- W HH O
O WW Gc W L A
WW
?' c W L I e OO HwO1 OO
(
!! O2 S
L -
LL Se L -
I PI WSaP A S
S Cl S
3 t
SPC' S
S R I
W P A FM RF I I I
-